A mass rat exodus hasn't been spotted yet, and city officials haven't gotten a flurry of rat reports.

But other experts believe many rats did make it out alive, using the same subway steps people do, and now pose an infection risk as they scrounge for food amid overturned trash bins and flooded grocery stores, National Geographic reported.

"It's not just about the high winds and rain. A rat disturbance is something we should be concerned about," Rick Ostfeld of the Cary Institute of Ecosystem Study in Millbrook, New York, told The Huffington Post.